Bose-402-II-Service-Manual 电路图 维修手册.pdf

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1、1 PROPRIETARY INFORMATION THIS DOCUMENT CONTAINS PROPRIETARY INFORMATION OF BOSE CORPORATION WHICH IS BEING FURNISHED ONLY FOR THE PURPOSE OF SERVICING THE IDENTIFIED BOSE PRODUCT BY AN AUTHORIZED BOSE SERVICE CENTER OR OWNER OF THE BOSE PRODUCT, AND SHALL NOT BE REPRODUCED OR USED FOR ANY OTHER PUR

2、POSE. Contents Safety Information.2 Electrostatic Discharge Sensitive (ESDS) Device Handling.3 Theory of Operation. 5-8 Figure 1. Block Diagram.8 Disassembly/Assembly Procedures. 9-11 Test Setup Procedure .12 402 Test Procedures . 13-15 802 Test Procedures . 16-18 Part List Notes.19 Figure 2. 402, 8

3、02 II Original Version Exploded View .20 Figure 3. 402, 802 II Current Version Exploded View.20 Main Part List. 21-22 402 Electrical Part List . 23-28 802 ? Electrical Part List . 29-35 402 ? Electrical Part List . 36-42 802 ? Electrical Part List. 43-48 402 and 802 ? Electrical Part List. 49-50 Pac

4、kaging Part List .51 Figure 4. Packaging Exploded View.51 Frequency Response Curves. 52-64 RadioFans.CN 收音机爱 好者资料库 2 1. Parts that have special safety characteristics are identified by the symbol on schematics or by special notes on the parts list. Use only replacement parts that have critical chara

5、cteristics recommended by the manufacturer. 2. Make leakage current or resistance measurements to determine that exposed parts are acceptably insulated from the supply circuit before returning the unit to the customer. Refer to Paragraph 84 of UL 1270. Use the following checks to perform these measu

6、rements: A. Leakage Current Hot Check-With the unit completely reassembled, plug the AC line cord directly into a 120V AC outlet. (Do not use an isolation transformer during this test.) Use a leakage current tester or a metering system that complies with American National Standards Institute (ANSI)

7、C101.1 “Leakage Current for Appliances” and Underwriters Laboratories (UL) 1492 (71). With the unit AC switch first in the ON position, then in the OFF position, measure from a known earth ground (metal water pipe, conduit, etc.) to all exposed metal parts of the unit (antennas, handle bracket, meta

8、l cabinet, screwheads, metallic overlays, control shafts, etc.), especially any exposed metal parts that offer an electrical return path to the chassis. Any current measured must not exceed 0.5 milliamp. Reverse the unit power cord plug in the outlet and repeat test. ANY MEASUREMENTS NOT WITHIN THE

9、LIMITS SPECIFIED HEREIN INDICATE A POTENTIAL SHOCK HAZ- ARD THAT MUST BE ELIMINATED BEFORE RETURNING THE UNIT TO THE CUSTOMER. B. Insulation Resistance Test Cold Check-(1) Unplug the power supply and connect a jumper wire between the two prongs of the plug. (2) Turn on the power switch of the unit.

10、(3) Measure the resistance with an ohmmeter be- tween the jumpered AC plug and each exposed metallic cabinet part on the unit. When the exposed metallic part has a return path to the chassis, the reading should be between 1 and 5.2 Megohms. When there is no return path to the chassis, the reading mu

11、st be “infinite”. If it is not within the limits specified, there is the possibility of a shock hazard, and the unit must be repaired and re- checked before it is returned to the customer. SAFETY INFORMATION RadioFans.CN 收音机爱 好者资料库 3 ELECTROSTATIC DISCHARGE SENSITIVE (ESDS) This unit contains ESDS d

12、evices. We recommend the following precautions when repairing, replacing, or transporting ESDS devices: Perform work at an electrically grounded work station. Wear wrist straps that connect to the station or heel straps that connect to conductive floor mats. Avoid touching the leads or contacts of E

13、SDS devices or PC boards even if properly grounded. Handle boards by the edges only. Transport or store ESDS devices in ESD protective bags, bins, or totes. Do not insert unpro- tected devices into materials such as plastic, polystyrene foam, clear plastic bags, bubble wrap or plastic trays. DEVICE

14、HANDLING RadioFans.CN 收音机爱 好者资料库 4 Dimensions:1.63 H x 19.0 W x 10 D (4.14 x 48.3 x 25.4 cm) Weight:5.5 lbs. (2.5 kg.) Chassis material:16 gauge steel with painted/zinc coated finish Cover plate material:Brushed aluminum, painted Input Connections:Balanced XLR Output Connections:Balanced high freque

15、ncy and low frequency XLR Input Impedance:Balanced input, -10 dB level: 14 k ? Balanced input, +4 dB level: 6 k ? Unbalanced input (+ input used), -10 dB level: 12 k ? Unbalanced input (+ input used), +4 dB level: 4 k ? Output Impedance:100 ? nominal Input Level:-10 dB or +4 dB, selectable Output Le

16、vel:8.0 Vrms max. 1 kHz into 10 k ?load Low Frequency (LF) Output Mode:Sum or normal LF Output Level: -18 dB to +3 dB, variable Crossover Frequency:140 Hz (Bi-amp mode), Roll-off slope: -18 dB/oct. Total harmonic distortion: 802:Midrange distortion of HF output: 0.2 % at 5.8 V, 700 Hz 402:Midrange d

17、istortion of HF output: 0.2% at 1.4 V, 850 Hz 402, 802:Low frequency distortion of LF output: 0.1 % at 160 mV, 80 Hz Output Noise:Bi-amp mode, HF outputs: 90V Bi-amp mode, LF outputs: 40V Passive mode: 90V Offset:All channels: 15 mV Power Requirements:120 VAC, 50/60 Hz, 12 Watts (US/Can.) 230 VAC, 5

18、0/60 Hz, 12 Watts (Eur.) 100 VAC, 50/60 Hz, 12 Watts (Japan) 240 VAC, 50/60 Hz, 12 Watts (Aus./UK) SPECIFICATIONS 5 THEORY OF OPERATION This discussion is an electrical overview of the 402 and 802 controllers. Equalization curves are referenced and are located in the back of this manual. Additionall

19、y, the block diagram and schematic diagrams should be referenced as required. 1. Differential Input Stage The input stage features protection against RFI (radio frequency interference), ESD (electro- static discharge), and overvoltage. Referring to the channel 1 circuit, R2/C1, R1/C120, R3/C2, and R

20、9, R10/C7 provide low pass filtering to reduce the possibility of RFI. Diodes D1-D4, D25, and D26 provide input clamping to protect against overvoltage and ESD. Op-amp U1 amplifies the difference between the + and - input pins, and converts it to a single ended signal that drives the equalizers. Gai

21、n switch S3 selects between two gains, a high gain setting for -10 dB sources and a low gain setting for +4 dB sources. 2. Equalizer for High Frequency Outputs Op-amps U1, U2 and U3 constitute the principal equalization for the high frequency output. Each stage makes a contribution to the total low

22、or high frequency contouring required by the loudspeaker. Op-amp U4 (pins 12, 13 and 14) implements a high pass filter suitable for the Full Range mode, while op-amp U4 (pins 8, 9, and 10) is selected for a high pass filter with a higher corner frequency for use in the Bi-amp mode. The circuitry is

23、duplicated for both channels. See the high frequency equalization curves for more information about the stage by stage response of the equalizer. 3. Output mode switch, Low frequency level control, and Normal/sum mode stage Output mode switch S2 (on the rear panel) controls op-amp summing amplifier

24、U6 (pins 5, 6, and 7). In the normal mode, the stage is not used, and the channel 1 and channel 2 low fre- quency outputs pass independent, 2-channel bass to 2 bass cabinets. In the sum mode, chan- nels 1 and 2 are combined, and this mono bass signal appears at the channel 1 low fre- quency output o

25、nly. Potentiometer R126 (on the rear panel), Low Frequency Level, provides for adjustment of the signal sent into the low frequency equalizer. 4. Equalizer for Low Frequency Outputs After the normal/sum stage, there is op-amp stage U7 (pins 12, 13, and 14) and op-amp equal- izer stages U7 (pins 8, 9

26、, and 10), U8 (pins 12, 13, and 14), and U8 (pins 8, 9, and 10). The equalizer provides high pass, low pass, and contouring equalization. See the low frequency equalization curves for more information about the stage by stage response of the equalizer. 5. Mode switch Rotary switch S1 is located on t

27、he rear panel. It selects the four operating modes for the con- trollers. Currently, position 3 (NC) is not used. 6 6. Output stage NOTE: The components mentioned in this paragraph are for the high frequency output only. The output stage is compatible with balanced signal transmission systems. Inver

28、ting op-amp stage U9 (pins 1, 2, and 3) provides the output signal. Diodes D9, D10, D29 and D30 provide output clamping to protect against overvoltage and ESD. Relays K1 and K2 clamp the outputs to ground to protect against power on/off transients. When the relay is de-energized, as when the AC powe

29、r is off, the outputs are clamped. About 1.2 seconds after the power is turned on, the relay is energized by transistor Q1 and allows audio to pass through the controller. When the power is turned off, a fast acting detector de-energizes the relays to protect against power off transients. NOTE: At t

30、he controller outputs, only the positive (+) output pin is driven. The negative (-) output pin is connected to signal ground through a series impedance identical to the positive (+) pin. When used to drive a balanced input, the controller output provides equal common-mode source impedances (100 ?).

31、This guarantees that any common-mode noise is induced equally into the positive (+) and negative (-) legs of a differential input in order to take full advantage of common-mode noise rejection. 7. Power Supply The controllers use only a nominal amount of power. Therefore, full wave bridge rectifier

32、Z1 and regulators U13 and U14 are all that are needed to develop the quiet, stable +/- 15 volt supply needed by the op-amps. 8. Turn On/Off Muting Circuit Relays K1 and K2 clamp the outputs and are controlled by three sections of quad comparator U15. U15 (pins 8, 9 and 14) drives the relay control t

33、ransistor Q1 by pulling the relay-coil termi- nal to nearly 15 volts . This energizes the relay for normal audio operation. At power on, U15 (pins 8, 9 and 14) is prevented from energizing the relay until capacitor C152 can be charged up sufficiently. This takes about 1.2 seconds, and mutes any turn

34、-on transients. At power off, U15 (pins 2, 4, and 5) quickly detects the loss of AC power and causes Q1 to snap quickly off. This de-energizes the relay in about 100 ms, before any transients can reach the output. 9. Troubleshooting Tips If a differential output test generator isnt available, connec

35、t the generator ground to the controllers ground terminal, and the generator hot lead to the negative (-) input terminal. Leave the positive (+) terminal unconnected. If you need to connect the controller outputs to a single-ended (not differential) instrument, connect the controllers output ground

36、to the instrument ground, and the controllers positive (+) output terminal to the instrument hot pin. Leave the negative (-) output pin unconnected. Since the controllers are two channel devices, you can troubleshoot any problem occurring in only one channel more easily by applying the identical sig

37、nal to both channel 1 and channel 2 inputs and tracing stage by stage, comparing the signal as it passes through the various stages. In general, the corresponding channel 1 and channel 2 stages share the left and right THEORY OF OPERATION hand sides of the respective op-amps. This makes it easier to

38、 compare the stages. 7 With a nominal AC power input voltage (100, 115, or 230, depending on the country), the AC voltages at the transformer secondary should be: between P3-1 and P3-3: 41.3 Vrms With a cold (i.e. -room temperature) power transformer, you should expect primary and second- ary resist

39、ances of: For the 100 VAC version: between P2-1 and P2-2: 41.8 ? between P3-1 and P3-3: 6.9 ? For the 115 VAC version: between P2-1 and P2-2: 45.4 ? between P3-1 and P3-3: 6.3 ? For the 230/240 VAC version: between P2-1 and P2-2: 195 ? between P3-1 and P3-3: 7.1 ? Other DC voltages are of use in tro

40、ubleshooting: Turn On/Off Muting Circuit Typical DC voltages after 2 seconds wake up U15-1Section not used U15-2+13.5 U15-3 -15.0 U15-4 +.15 U15-5 +3.2 U15-6Section not used U15-7Section not used U15-8 +7.5 U15-9+13.5 U15-10+7.5 U15-11+9.7 U15-12-15.0 U15-13+13.5 U15-14-13.9 Q1-collector-14.7 Power

41、Supply U13-1+26.0 U14-2 -26.0 THEORY OF OPERATION 8 THEORY OF OPERATION Figure 1. Block Diagram 9 DISASSEMBLY/ASSEMBLY PROCEDURES 402 and 802 ? First Variation (Removable Front Panel) 1. Top cover Removal 1.1 Remove the two screws (7) that secure the top cover (2) to the front panel (9). 1.2 Remove

42、the two screws (1) that secure the top cover to the rear of the chassis. 1.3 Lift up the rear of the top cover and slide it out from under the front panel. 2. Top cover Replacement 2.1 Place the top cover (2) onto the unit and slide it under the front panel (9). 2.2 Secure the rear of the top cover using the screws (1) removed in procedure 1.2. 2.3 Secure the front of the top cover using the two screws (7) removed in procedure 1.1. 3. Front Panel Removal 3.1 Perform procedure 1. 3.2 Remove the two wi